Speaking as a museum collection care professional, may I suggest that if
you have specimens in transit, you do not use any biodegradable
packaging materials? If they come into contact with water or fluids in
which your specimens are packed, they shrink thereby reducing the
cushioning and stabilizing they were supposed to afford to your precious
beasties (plants?). The resulting goo is also pretty awfull!
Judith C. Price
Canadian Museum of Nature